At that tender age, Silverblatt's family took him to see "The Sound of Music," thinking the young bookworm might enjoy the show because the cast included children.

Instead of being delighted by the prospect, Silverblatt says, "I was not good at playing with children, and I was terrified that they were going to ask me to go up onstage and play with the children." Luckily, Silverblatt was not faced with this social torture, and instead "The Sound of Music" inspired in him a lifelong passion for musical theater.

As part of that passion, Silverblatt developed a special bond with Sondheim by working the British-style Cryptic Crosswords that the composer/lyricist created for New York Magazine earlier in his career. "The definitions were very tricky," Silverblatt says. "Here's a sample clue: 'Broken harmonicas floating in Manhattan.' You 'break' harmonicas and rearrange the letters to get 'maraschino' -- the cherries floating in the drink called a Manhattan. The puzzles reshaped my way of looking at words."

Now, after all these years, Silverblatt will be side by side with Sondheim-- and Sondheim's frequent collaborator, John Weidman -- for a discussion of the tangled evolution of the Sondheim-Weidman musical "Road Show."

The program, titled "Lyrics as Literature," will air Thursday from 2:30 to 3 p.m. on the public radio station KCRW-FM (89.9).

"Road Show" began its life in 1999 at the New York Theater Workshop under the title "Wise Guys." Rewritten and titled "Bounce," it was produced in Chicago and Washington in 2003. The musical, with lyrics by Sondheim and book by Weidman, was revised again and premiered off-Broadway (with greater success) as "Road Show" in 2008, directed by John Doyle. The show tells the story of brothers Addison and Wilson Mizner and their adventures across America from the Alaskan Gold Rush to the Florida real estate boom in the 1930s.

Given his history with Sondheim, it's not surprising that Silverblatt was paying enough attention to notice when a new recording of the 2008 production was released June 30. It was time to swallow his fear and approach the press-shy Sondheim.

Silverblatt wrote to Sondheim's touring agent, who said he would forward Silverblatt's letter. With trembling fingers, Silverblatt rewrote his missive directly to Sondheim, telling of the depths of his own obsession with musical theater. He also confessed his addiction to the puzzles.

"The next day, I got a note back saying: 'How can I turn down such a generously worded request?" Silverblatt says, still sounding surprised. Sondheim arranged for Weidman to join the conversation, which was recorded a few weeks ago at Carnegie Hall.

Silverblatt says he was honored that the 79-year-old musical theater legend would take time for "an absolute stranger from across the country." And despite the checkered history of "Road Show," he adds: "This is, and will be, the classical American musical; it will be on the special list of things that shape America, the way Americans look at themselves."

For those who share Silverblatt's taste for Sondheim, his musical "Putting It Together" just opened at South Coast Repertory. Check back with Culture Monster on Sunday for The Times' review.

-- Diane Haithman

Top photo: Stephen Sondheim, Harold Prince and John Weidman before the Goodman Theatre production of "Bounce." Credit: Chuck Berman / Chicago Tribune.